Usb how much current can it supply

Over the last decade, the USB port has been the most recognized component in electronics, aside, of course, from the smartphone. Some end-users even base their desktop and laptop purchases on whether there are enough USB ports. The USB port has bridged the gap of communication between a myriad of devices that are otherwise physically incompatible. The fact that we are in our third series generation for the component speaks volumes to its popularity and widespread use. This becomes especially important when the device you wish to charge or use requires a USB 3.

So much so that it persuaded PC manufacturers to implement them into their board designs. To put it mildly, USB 1. However, with USB 1. Like all things in the field of electronics, the USB standard progressed and evolved, thus ushering in the standard USB 2.

In the spring of , the USB 2. Also, with the newer standard came increased data rates. The specifications for USB 2. USB has come a long way since its inception; however, remains a standard.

The USB 3. Moreover, it is being called the one-port revolution since USB 3. USB 3. Also, with the increase in data rate comes an increase in bus power , i. In a USB network, there is one host and one device. In almost every case, your PC is the host, and your smartphone, tablet, or camera is the device. Power always flows from the host to the device, although data can flow in both directions, such as when you copy files back and forth between your computer and your phone.

Up to DisplayPort 2. To the end-user, the switch to Thunderbolt should be seamless and unnoticeable. A regular USB 1. USB 3. In terms of actual current milliamps or mA , there are three kinds of USB ports dictated by the current specs: a standard downstream port, a charging downstream port, and a dedicated charging port. In the USB 1. The charging downstream and dedicated charging ports provide up to 1,mA 1. It also supports a power draw of 1. USB-C is a different connector entirely.

But there can also be older-style USB ports that support the 3. However if you need the high current and connected to the PC at the same time, consider investing in a hub that have it's own supply from the mains. The above mA current upto mA can be negotiated by the device driver. If this setting is off - you may find yourself re-plugging the device after booting up, in case if it does not work properly.

Only with this setting on, if present, the BIOS will provide a current greater than some minimum value, I think mA. It is limited by design. Good news is you can find out what your ports are rated for. If older than 5 yrs some may be mA, but newer than that, I doubt it. If running Windows I hope this helps!! I found moving a mouse to each port the easiest way to identify, but my learned colleagues may know a faster way. But I have seen at least one motherboard with blown electrolytic caps near the USB ports due to current surges, detected with the traditional popcorn bulging lid.

Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Asked 11 years ago. Active 1 year ago. Viewed k times. If you need 1. Some probably can, though. I have used a couple that would even shutoff the port if there was too capacitive of a load and you violate the input rush current. There is no upper limit. Show 2 more comments.

Active Oldest Votes. USBmA When a device is connected it goes through enumeration. Summing it up You may pull mA from a computer port.

Please let me know if there is anything I can add. Kortuk Kortuk The fact that it is common for a device to allow mA does not mean I would want to design my devices to immediately trust mA is available, I would instead design to wait for enumeration to complete. I am open to learning that I can do otherwise though.

Many of my links that I have given list that as a requirement of the standard. I've seen only one laptop that did this. Show 14 more comments. Add a comment. On USB 3. Computers usually do not support 1. You could get that much by placing a resistor between data wires to signalize that device is only using power and not transmitting data and use USB cell phone charger or similar device dumb power source.

I'll have to go home and take mine apart to see what the circuit is How else would the end device know how much it is allowed to draw from the port. Supports BC1. Some smartphones can also use a 2A charger e. Samsung Galaxy Note II. Choose a USB charger that delivers power with control Cambrionix industrial USB hubs auto-detect attached devices and automatically adjust the current output to the highest level permitted by the device manufacturer and USB specifications.

Want to find out more? Read the BC1. Why charging at the wrong level could damage your device. Charging devices not at their optimum charging level has a number of issues. Charging from a computer USB 2.

Charging from a computer USB 3.